DO 2004/105536 A1 discloses a touch fastener in which the free ends of the stems of the individual bonding elements are provided with a plurality of individual fibers. The diameter of the respective fibers is chosen to be very thin so that on the free end of each individual fiber only a very small contact surface ranging from 0.2 to 0.5 μm is available.
These orders of magnitude, which in preferred embodiments can also be in the nanometer range, enable interaction with a corresponding body in the vicinity on which the touch fastener is to be attached, by van-der-Waals forces classically regarded as a subgroup of adhesion. The conventional touch fastener has good connection properties, but is tied to a correspondingly costly production process.
This problem also applies to a touch fastener according to publication WO 01/49776 A2 which provides indications to one skilled in the art to use parts of the foot structure of a gecko directly as biological material, or to artificially imitate it. This adhesive structure has a plurality of spatulae components with each divided into a plurality of individual filaments in the form of a bent cylindrical fastener element on the free end.
Conversely, for simplified production, DE 102 23 234 B4 proposed a method for surface modification of an object, in the form of a fastener part with the objective of increasing the adhesion capacity of the bonding element. For this purpose, the free surface is subjected to structuring to form a plurality of projections, with each provided with a foot part and a head part. The head part has a face surface oriented away from the surface. Each projection is formed with a size such that all face surfaces have the same vertical height over the surface. This arrangement yields an adherent contact surface interrupted by mutual distances between the face surfaces. The foot parts of the projections are tilted relative to the surface normals of the surface.
It is possible with this known solution to make available the implementation of detachable bonding connections for an extended range of materials, with increased adhesion capacity and the possibility of enabling the setting of predetermined adhesion forces or properties. However, based on the relatively rigid arrangement between the head and backing by the optionally tilted stems, there is still opportunity for improved solutions.